I used loctite power grab to glue the panels onto the insulation. We didn’t use luan, but a plastic sort of wall panel. NRP panels from Lowe’s. The first panel went right on and hubs and I only had to hold in place for about 3 minutes and it was fine. A few months later the 2nd panel we tried kept falling down so we are going to cut it in half to reduce the weight of it and try again this week.